電磁最佳化實驗室EM Optimization LabYen-Sheng Research Group, Department of Electronic Engineering

In this paper, an anisotropic metasurface operating at 28 GHz is proposed. Gain of the signal wave can be enhanced when transmitting through the metasurface, and at the same time, the signal wave reflected back to the metasurface can be reflected and enhanced again. This study demonstrates the flexible control of electromagnetic waves by Metasurface, and the ability to gain enhancement, polarization conversion, asymmetric transmission, and anisotropic without the active components. Fabry-Pérot structured polarization converter and grating are used to achieve an anisotropic metasurface with asymmetric propagation. The transmission and reflection modes of the metasurface are controlled by the polarization of the incident wave. Unlike the previous paper that requires active circuits to control, this method is simpler and more compact. This study achieved the ability of metasurface has gain enhancement, polarization conversion, asymmetric transmission, and anisotropy at the same time. The quasi-Yagi antenna is used as the feed antenna with a gain of 8.0 dBi and incident on the proposed metasurface. Among them, the ability to gain enhancement, the peak gain is 18.6 dBi when it is used as a transmission array, the HPBW of E-Plane H-Plane are 5.8° and 5.1°, the aperture efficiency is 4.6 % ; and the peak gain is 16.4 dBi when it is used as a reflective array, the HPBW of E-Plane H-Plane are 7° and 6.9°, the aperture efficiency is 2.8 % ;  and the peak gain in the focusing direction is 20.3 dBi when it is used as a transflective array, the HPBW of E-Plane H-Plane are 6.9° and 5.8°, the aperture efficiency is 6.8 %.